The practice of surgery . not unfrcquently, it is of a rheumatic character. IRITIS, 133 Fig. 39. A pink or brick-red vascular zone is seen on the sclerotic, formed bythe minute subdivisions of the anterior ciliary arteries. This zone ismost distinct near the edge of the cornea,and becomes gradually shaded off towardsthe circumference of the globe; it is moreor less marked, according to the extent andstage of the inflammatory action. Thereis at first a distinct interspace of white be-tween the vascular zone and the cornealmargin ; ultimately, this white line becomesobscured by involvement of th
The practice of surgery . not unfrcquently, it is of a rheumatic character. IRITIS, 133 Fig. 39. A pink or brick-red vascular zone is seen on the sclerotic, formed bythe minute subdivisions of the anterior ciliary arteries. This zone ismost distinct near the edge of the cornea,and becomes gradually shaded off towardsthe circumference of the globe; it is moreor less marked, according to the extent andstage of the inflammatory action. Thereis at first a distinct interspace of white be-tween the vascular zone and the cornealmargin ; ultimately, this white line becomesobscured by involvement of the conjunctivalvessels in the inflammation. The pupil iscontracted, and much less movable than inhealth, under the ordinary stimulus oflight. Indeed, returning mobility of thispart is one of the first and surest signs ofamendment having fairly The irischanges its hue; if of a light color natu-rally, it becomes greenish ; if dark, it as-sumes a reddish-brown appearance. It isalso perceptibly swollen, or thickened at. Iriti>; showing the characteristic vas-cularity of the globe, the iris clogged withlymph, the pupil contracted and irre-gular. 1 Gromelli, from the observation of successful injection, concludes the iris to be anerectile tissue. He supposes that contraction of the pupil, during the inflammatory pro-cess, depends simply ou engorgement of the radiating vessels, which are fixed at the cir-cumference, and free at the pupillary margin ; and that return of the blood, in resolution,allows the iris to shrink, and the pupil consequently to expand.—Brit, and For. Rev. , p. 233. [The existence of muscular fibres in the human iris, as the cause of the contraction anddilatation of the pupil, long suspected, has been recently satisfactorily proved by , of England. An interesting account of his investigations upon this subject is con-tained in the first No. of the Quarterly Journal of Microscopical Science. Mr. Lister has shown that a distinct sphincter a
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